U.S. President Barack Obama stressed the importance of economic development and cooperation for North America while attending a North American leaders' summit in Mexico Wednesday. The meeting with Mexican President Enrique Pena Nieto and Canadian Prime Minister Stephen Harper in the central city of Toluca has focused on deepening ties between the three countries, Obama said, adding that they share common principles such as democracy and free trade. Free trade between the three countries is part of an integrated supply chain that allows them to sell their products and services around the world, Obama said. "We have every incentive to make this work," he said, urging the business sector to help push for progress for North America. The United States, Canada and Mexico will always have "parochial interests," Obama pointed out, saying the strength of the relationship between the three countries is not a matter of government policy, but arises from "our people, businesses, commercial ties and cultures." The 7th North American Leaders' Summit was held under the theme of "North American Competitiveness."